Microbial adhesins recognizing extracellular matrix macromolecules

The pathogenic fungus Sporothrix schenckii is the causative agent of sporotrichosis. This subcutaneous mycosis may disseminate in immunocompromised individuals and also affect several internal organs and tissues, most commonly the bone, joints and lung. Since adhesion is the first step involved with the dissemination of pathogens in the host, we have studied the interaction between S. schenckii and several extracellular matrix (ECM) proteins. The binding of two morphological phases of S. schenckii, yeast cells and conidia, to immobilized type II collagen, laminin, fibronectin, fibrinogen and thrombospondin was investigated. Poly (2-hydroxyethyl methacrylate) (poly-HEMA) was used as the negative control. Cell adhesion was assessed by ELISA with a rabbit anti-S. schenckii antiserum. The results indicate that both morphological phases of this fungus can bind significantly to type II collagen, fibronectin and laminin in comparison to the binding observed with BSA (used as blocking agent). The adhesion rate observed with the ECM proteins (type II collagen, fibronectin and laminin) was statistically significant (P<0.05) when compared to the adhesion obtained with BSA. No significant binding of conidia was observed to either fibrinogen or thrombospondin, but yeast cells did bind to the fibrinogen. Our results indicate that S. schenckii can bind to fibronectin, laminin and type II collagen and also show differences in binding capacity according to the morphological form of the fungus.

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“…Primary adhesion of endothelial and/or (24). Type II collagen is present in hyaline cartilage, as well as in vitreous humor (25).…”

Section: Discussionmentioning

confidence: 97%

Adhesion of the human pathogen Sporothrix schenckii to several extracellular matrix proteins

Lima

Figueiredo²,

Pereira³

et al. 1999

Braz J Med Biol Res

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“…CNA) containing almost exclusively repeated Ig-like folds. At the Cterminal end of the S. aureus MSCRAMMs are features required for cell-wall anchoring, including an LPXTG (X being any amino acid residue) motif preceded by a cellwall-spanning domain, followed by a hydrophobic transmembrane region and, finally, a cytosolic tail composed of a short sequence rich in positively charged amino acid residues (Patti & Hook, 1994). The LPXTG motif is recognized by a transpeptidase called sortase which is responsible for catalysing the covalent linking of these proteins to the staphylococcal cell wall (Mazmanian et al, 2001;Schneewind et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

A family of putative MSCRAMMs from Enterococcus faecalis

et al. 2004

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The recently published Enterococcus faecalis genome [Paulsen, I. T., Banerjei, L., Myers, G. S. & 29 other authors (2003). Science 299, 2071–2074)] was examined and 41 putative cell-wall-anchored proteins were identified. Seventeen of these proteins are predicted to contain tandemly repeated immunoglobulin-like folds characteristic of the structural organization of staphylococcal adhesins of the MSCRAMM (microbial surface component recognizing adhesive matrix molecules) type. Two of the nine proteins selected for further study appear to represent cell-wall-anchored enzymes. It is proposed that the remaining seven proteins constitute a family of structurally related proteins potentially interacting with proteins of the host. This family includes the previously identified collagen/laminin-binding MSCRAMM ACE [Rich, R. L., Kreikemeyer, B., Owens, R. T., LaBrenz, S., Narayana, S. V., Weinstock, G. M., Murray, B. E. & Hook, M. (1999). J Biol Chem 274, 26939–26945]. It is further demonstrated that genes encoding the seven putative MSCRAMMs are present in all E. faecalis strains tested and these proteins appear to be expressed during infection in humans, since sera from infected individuals contain antibodies reacting with recombinant versions of the enterococcal proteins.

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“…This type of adhesion is mediated by specific fungal cell-surface components called adhesins, which frequently bind ECM proteins [104]. Recently, the presence of these adhesins on the surface of both P. brasiliensis conidia and yeast cells has been demonstrated [100,101,105].…”

Section: Expression Of Extracellular Matrix Proteinsmentioning

confidence: 99%